Reversing gear for steam engines with poppet valve gear, especially for locomotive and marine steam engines



H. LENTZ March 7, 1939.

REVERSING GEAR FOR STEAM ENGINES WITH POPPET VALVE GEAR,

ESPECIALLY FOR LOCOMOTIVE AND MARINE STEAM ENGINES 4 Sheets-Sheet 1 Filed Dec. 16, 1935 lnuemon' (m 7 March 7, 1939. H. LENTZ 2,149,353

RBVERSING GEAR FOR STEAM ENGINES WlTl-I POPPET VALVE GEAR, ESPECIALLYFOR LOCOMOTIVE AND MARINE STEAM ENGINES Filed Dec. 16, 1935 4 Sheets-Sheet 2 March 7,

H. E REVERSING GEAR FOR STEAM ENGINES WITH POPPET VALVE GEA ESPECIALLY FOR LOCOMOTIVE AND MARINE STEAM ENGINES Filed Dec; 16, 1935 III/1,14 YIIIII/Z VIII/ll 4 Sheets-Sheet 3 March 7, 1939. H LENTZ 2,149,353

REVERSING GEAR FOR STEAM ENGINES WITH POPPET VALVE GEAR. ESPECIALLY FOR LOCOMOTIVE AND MARINE STEAM ENGINES Filed Dec. 16, 1935 4 Sheets-Sheet 4 70a 73 a o i0? 70 1 7,; N I y I g k\\\\\\\\ )E 7A J I! 0A.. l I "11:13) 77 I 77a E i E g I 75 lnventor. M Z402.

PatentedMan7- 1939 PATENT orricaf aavaasno Gm non emu enemas wrrn POPPET vanvn cam, asrnomnu FOR LOCOH ENGINES OTIVE-AND mama STEAM Hugo Lents, Berlin-Halensee, Germany Application December 16, 1935, Serial No. 54,718 In Germany December 19, 1934 4 Claims. 01. 121-127) This invention relates to the construction of the reversing gear of valve steam engines, especially locomotives and marine engines with poppet valve gear, in which the valves are actuatediby oscillating control cams. According to the in-, vention the admissionand exhaust valv;es are separately controlled from two different oscillating points or movable parts of a reversing element (link or eccentric), so that, when adjusting the gear for different charges, the path of the control points for the admission valve is always farther from the centre of the shaft than the path of the control point for the exhaust valve. Thus, with the same displacement path the angul5 lar displacement of the control point for the exhaust valve is always greater than the angular displacement of the control point for the admission valve. Different angles of lead correspond to these angular displacements, the angle of lead 20 for the admission valve being greater than that for the exhaust valve.

This presents the advantagethat, with in- I creased charge, that is when larger quantities of steam are supplied, the exhaust valves will be 25 held open for a longer period so that in the case of a large charge the compression will commence later and the larger quar tity of steam can more ing drawings, in which Fig. 1 shows diagrammatically the'end elevation of a locomotive 'with valve motion drive according to the invention.

' 40 Fig. 2 is a section on line II-II of Fig. 1 in larger scale. 1 Fig. 3 is a section on line ]I[l1I of- Fig. 2 in larger scale.

Fig. 4 is a. section on line IVIV of Fig. 2.

45 Fig.5 is a section on line V-V'of Fig. 1 through the reversing shaft housing on larger scale, the

driving gear of the reversing shafts-mounted the one in the other being situated on the one side of the machine.

' 50 .Fig.,6 shows a section through the valve housing situated on the one cylinder side of a steam engine controlled according to the invention, in.

which the admission and exhaust-valves on each cylinder side are lying side by side, and the valves 55 of each kind are controlled by a separate reverslustrated by way of example in the accompany-.

ing shaft, the driving gears for the reversing shafts being mounted on different sides. of the n ne.

Fig. 7 shows a section through the valve housing and the gear drive in a steam engine with 5 admissionand exhaust-valve arrangedthe one behind the other at each end of the cylinder.

Fig. 8 is a section on line VIII-N111 of Fig. 7. Fig. 9 shows a diagram of the eccentric adjusting.

' 11 either side of the frame I the steam cylinders 2 of the locomotive are mounted. Every cylinder carries at the top the valve housing 3 in which the admission and exhaust channel for the steam, the admission and exhaust valves and in a separate chamber 4 the reversing shafts with the reversing cams l2 are accommodated. In the form of construction shown in Fig. 5, the hollow reversing shaft ID with control cams I 2 acts, by means of intermediate levers I2a, upon the spindies of the admission valves. Shaft II is mounted in the hollow shaft- Hi and carries a control cam ll which,'by means of intermediate levers Ila, acts upon the spindles 23 of the exhaust valves. v c

The reversingshafts i0 and l I are driven from a rotating shaft l1 transversely mounted on the frame and by means of adjusting eccentrics 22 and 23. The rods 22a'and 23a. of the eccentrics engage on the lever arms Ilia and Ho keyed "on the ends of shafts l0 and II. The hollow' shaft I1 is driven from one of the driving wheels of the locomotive through a transmission gear, as disclosed in the U. S. A. application Ser. No. 114,190 filed December 4; 1936. The adjusting eccentrics 22 and 23 are, in the form of construction shown in Figs. 2 and 3, constructed as step eccentrics, in which as shown in Fig. 3 both eccentric faces are arranged so that they correspond to the control diagramshown in 40 Fig. 9 which. will hereinafter be described and that consequ'entlythe exhaust eccentric in the f median position has a smallereccentricity than the admission eccentric.

The setting body I. is shiftably mounted in a cross-section of the hollow shaft l1 limited by two ring-flanges 30 on a prismatic element 3| connecting the ring-flanges. With this object in view the setting body l8 has a longitudinal slot 32. On one side of the slot 32 a serrated plate I9 is inserted, the teeth of which mesh with the teeth 23 of an axially shiftable adjusting rod 2| mounted in the hollow shaft II. The teeth are directed obliquely to the direction of adjusting so that, when the rod 2| is shifted in the direc- I is connected tion of thearrow A, the setting body I8 is shifted on the prismatic element 3| in the direction oi? the arrow B, and inversely.

The axial-shifting of rod 2| is eflfected thereby that at theend of the same a bush 32 having obliquely adjusted teeth 34 is arranged, in which teeth the teeth 33 of a second upwardly extending adjusting rod 36 engage in such a manner that during the axial adjusting of the rod 36 the adjusting rod 2|; is shifted inthe hollow eccentric shaft I]. The end of the adjusting rod 2| with the bush 33 and the adjusting rod 35 are mounted in bores of a housing 31, said bores being directed perpendicularly the one to the other. The end of the adjusting rod, 36 projecting in upward direction from the housing 31 with a bell crank lever 38 which, by a rod system not shown in detail, can be attended from the engineer's cab on the locomotive.

In Fig. '9 the diagram of the adjusting of the eccentrics is illustrated, 0A showing the smallest eccentricity of the discharge eccentric and OE the smallest eccentricity of the admission eccentric for zero-charge. It both eccentrics are shifted-by the adjusting rod 2| by the same distance, E is displaced, for instanceif the charge amounts to 20%, to E and point A to A. CE is then the eiiective eccentricity for the admission and 0A 'the efiective eccentricity for the exhaust, the angular displacement for .the exhaust being greater than the angular displacement for the admission. The exhaust valve is therefore maintained open, with larger charge, for a longer time so that the compression begins later.

In Figs. 2 and 3 the two eccentrics 22 and 23 are united on one adjusting body. The two eccentrics may, however, be arranged separate the one from the other on the hollow shaft l1 and actuated from the same adjusting rod 2| but ,with different tooth pitches. This arrangement is for instance employed in the valve arrangement shown in Fig. 6, in which in the gear housing it the lay shaft In with the admission controLcam i2 is situated on the one .side of the cylinder and the control shaft II with the control cam I4 for controlling the :exhaust valve is situated on the'other side of the cylinder.

In Figs. '7 and 8 a valve arrangement with its the manner of rolling levers.

control gear is shown, in which the admission and exhaust valves are situated co-axially one .behind the other at each end of the cylinder and the spindle 25 of the admission valve l3 extends through the hollow spindle 26 of the exhaust valve. =Discs mounted on the ends of the two valve spindles bear against the ends of intermediate levers 33 actuated by the operating cranlm l2, H of the lay shafts l0 and II. The cranks and the intermediate levers contact after As can be seen, it is also possible in this arrangement to separately adjust the admission and exhaust valves in the sense of the invention.

I claim:-

l. A reversing gear for steam engines, especially for locomotive and marine steam engines with poppet valve gear with oscillating control cams, comprising in combination with the admission and exhaust valves, a shaft, a reversing element on said shaft having two differently oscillating control points adapted to actuate said admission and exhaust valves respectively, means forgadjusting said element for difierentcharges, the path of the control point for the admission valve being away farther from the centre of the shaft than the path of the control point for the exhaust valve, so that during the adjustment the angles of advance for the admission valve and the exhaust valve change so thatthe exhaust valve is held open longer as the charge increases.

2. In areversinggear as specified in claim 1, a double adjusting eccentric, and two differently adjusted driving eccentrics for the admission valves and for the exhaust valves.

3. In a reversing gear as specified in claim 1,

a double adjusting eccentric, and two differently adjusted driving eccentrics for the admission valves and. for the exhaust valves, the eccentric for operating the exhaust valves having a smaller eccentricity than the eccentric for operating the admission valves.

4. In a reversing gear as specified in claim 1 eccentrics for the admission valves and eccentrics for the exhaust valve arranged separately the one from the other, and an adjusting rodfor operating all said mechanisms and having teeth with difi'erent pitches one pitch for each eccentric.

HUGO LEN'IZ. 

